Hướng dẫn compress file mdf sql server
Recover Data for SQL Server là phần mềm mạnh mẽ được dùng để khôi phục các file database SQL Server (.MDF) bị lỗi, được tạo ra bởi SQL Server 2000/2005/2008. Show
Nó có thể khôi phục thành công những file .MDF bị lỗi và không thể mở được do các nguyên nhân như: lỗi hệ thống, format hoặc cài đặt lại. Ngoài ra, nó còn cho phép bạn xem và lưu trữ dữ liệu đã khôi phục vào địa điểm đã xác định. Tính năng cải tiến:• Giao diện trực quan, đơn giản, dễ sử dụng. • Khôi phục dữ liệu nhanh chóng. • Khôi phục file database SQL Server (.MDF) bị lỗi. • Dễ dàng khôi phục dữ liệu trên server khi SQL Server vẫn đang chạy. • Quét và khôi phục dữ liệu từ các database SQL có dung lượng lớn. • Khôi phục các thuộc tính như Tables, Indexes, Views, Triggers, Constraints, Functions, Procedures,… It's a pretty widely debated topic. Another answer to this question gives you a more in-depth backstory on it, so I won't duplicate that here. Anyone know about performance impacts When it comes to the performance of what you're suggesting, there's not a single answer that works for everyone. It's dependent on a couple of things:
Different answers to the above questions will result in vastly different changes to performance. If you're doing the compression on an end-user PC, then you'll potentially notice some benefits; if the data can be compressed very well (and quickly enough), then sending the data to the database might take less time than sending the uncompressed version. Though, if the data can't be compressed very well (or compresses very slowly), then your end-users might complain about a decrease in performance; it may take less time to send it to the server, but the only thing your end-users will notice is the loading bar while the data is being compressed. You might be able to get around this by conditionally compressing files that are known to compress very well, such as text documents. If the compression is being performed on a web server, which then writes it to the database, you likely won't see a lot of benefit in terms of speed. Servers are usually connected to each other over very fast connections (usually 100/1000mbit connections if they're in the same data center) and you will have already incurred the most likely bottleneck: the upload speed of the user's internet connection. At this point you're just putting more load on your web server that could potentially be better spent servicing a greater number of concurrent users of your web application. Of course, you could always upload the files to a staging directory and perform the compression at off-peak hours, but then you've added a lot of complexity (what if the file is requested again before it is compressed and sent to the database?) just to save a few megabytes on your server. Furthermore, you're going to incur a similar performance cost every time a file is requested, since you'll have to spend time and processing power decompressing it. If you get many requests to download files in a short period of time, your server could slow to a crawl trying to decompress everyone's files before sending them down the wire. As I said in the beginning, there's no single answer to this that will work for everyone, but if you consider all the factors, you can make an informed decision about what will work best for your environment. No, but SQL Server 2008 does provide data compression at the ROW or PAGE level on a table by table basis. I am looking at this myself right now. I have compressed the top 10 tables in one of our databases and dropped the spaced used by 3 GB. The first 4 tables dropped the space used by 2 GB, the next 6 only reduced it by another 1 GB. I am looking at PAGE compression at the moment. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. Data compression
In this articleApplies to: SQL Server, Azure SQL Database, and Azure SQL Managed Instance support row and page compression for rowstore tables and indexes, and support columnstore and columnstore archival compression for columnstore tables and indexes. For rowstore tables and indexes, use the data compression feature to help reduce the size of the database. In addition to saving space, data compression can help improve performance of I/O intensive workloads because the data is stored in fewer pages and queries need to read fewer pages from disk. However, extra CPU resources are required on the database server to compress and decompress the data, while data is exchanged with the application. You can configure row and page compression on the following database objects:
For columnstore tables and indexes, all columnstore tables and indexes always use columnstore compression and this isn't user configurable. Use columnstore archival compression to further reduce the data size for situations when you can afford extra time and CPU resources to store and retrieve the data. You can configure columnstore archival compression on the following database objects:
Note Data can also be compressed using the GZIP algorithm format. This is an additional step and is most suitable for compressing portions of the data when archiving old data for long-term storage. Data compressed using the Row and page compression considerationsWhen you use row and page compression, be aware the following considerations:
For a list of features supported by the editions of SQL Server on Windows, see:
Columnstore and columnstore archive compressionColumnstore tables and indexes are always stored with columnstore compression. You can further reduce the size of columnstore data by configuring an additional compression called archival compression. To perform archival compression, SQL Server runs the Microsoft XPRESS compression algorithm on the data. Add or remove archival compression by using the following data compression types:
To add archival compression, use ALTER TABLE (Transact-SQL) or ALTER INDEX (Transact-SQL) with the
1 option and
2. For example:
To remove archival compression and restore the data to columnstore compression, use ALTER TABLE (Transact-SQL) or ALTER INDEX (Transact-SQL) with the
1 option and
4. For example:
This next example sets the data compression to columnstore on some partitions, and to columnstore archival on other partitions.
PerformanceWhen you compress columnstore indexes with archival compression, this causes the index to perform slower than columnstore indexes that don't have the archival compression. Use archival compression only when you can afford to use extra time and CPU resources to compress and retrieve the data. The benefit of archival compression is reduced storage, which is useful for data that isn't accessed frequently. For example, if you have a partition for each month of data, and most of your activity is for the most recent months, you could archive older months to reduce the storage requirements. MetadataThe following system views contain information about data compression for clustered indexes:
The procedure sp_estimate_data_compression_savings (Transact-SQL) can also apply to columnstore indexes. Impact on partitioned tables and indexesWhen you use data compression with partitioned tables and indexes, be aware of the following considerations:
How compression affects replicationWhen you use data compression with replication, be aware of the following considerations:
The following table shows replication settings that control compression during replication. User intent Replicate partition scheme for a table or index Replicate compression settings Scripting behavior To replicate the partition scheme and enable compression on the Subscriber on the partition. True True Scripts both the partition scheme and the compression settings. To replicate the partition scheme but not compress the data on the Subscriber. True False Scripts out the partition scheme but not the compression settings for the partition. Not to replicate the partition scheme and not compress the data on the Subscriber. False False Doesn't script partition or compression settings. To compress the table on the Subscriber if all the partitions are compressed on the Publisher, but not replicate the partition scheme. False True Checks if all the partitions are enabled for compression. Scripts out compression at the table level. Effect on other SQL Server componentsApplies to: Compression occurs in the Database Engine and the data is presented to most of the other components of SQL Server in an uncompressed state. This limits the effects of compression on the other components to the following factors: How to manage MDF database size in SQL Server?SQL Server compression is a better way to manage MDF database size. Microsoft SQL Server provides a different type of compression for tables and indexes. In addition, it offers archival compression also to reduce database size. Now, in order to reduce the size of MDF file, a DBA can use the data compression tool. How many GB is a MDF file?Total space in hard disk is 136 GB, the .MDF file size is 124 GB, and the log file size is 2 GB. I have only 12 GB free space and while running the shrink command on the .MDF file, logs are growing and consume the free space -- low disk spaces throws the shrinking into a no respond state. How to reduce the size of MDF file?Now, in order to reduce the size of MDF file, a DBA can use the data compression tool. Apart from minimizing the physical database size, it reduces a total number of disk I/O and improves the performance of database application. Does DBCC shrinkfile reduce the size of an MDF?Have you reviewed existing questions about shrinking MDFs, here on DBA.SE? Yes.Sine the initial size is set as 1.6TB ,the minimum shrink size is also 1.6TB.I want o reduce the initial size so that i can shrink it to a smaller size > inital size. DBCC SHRINKFILE will reduce the size of an MDF, if there's free space available to release. |